Drying apparatus



Aug. 20, 1940. J, F DIETRICH 2,2L767 DRYING APPARATUS Filed Jan. 24, 1938 5 Sheets-Sheet l "Ill/ll/ .a Tl lA RR. Tm@x mAH. DGa ..NJ FHd .Re JDN... F w. 9 l 01 2 uw u 5 sheets-sheet 2 Aug. 20, 1940. J. F. DIETRICH DRYING APPARATUS s sheets-'sheet :s

Filed Jan. 24, 1958 Patented Aug. 20, 1940 UNITED: STATES PATENT OFFICE l DRYING APPARATUS Julius F. Dietrich, Sheboygan, `Wis.; Richard H. Dietrich administrator of said Julius F. Dietrich, deceased Application January 24, 1938, Serial No. 186,614

15 Claims. (Cl. 159-5) The apparatus of the present invention is deagainst which the adjoining ends of `the intersigned primarily for the drying of milk, `although mediate 'and upper casing sections abut and are it is adapted for other uses. The principal object held by theA provisionV of bolts Ivv which pass and purpose ol the invention is to so construct through a` ange I6 on the rim of the upper secsurface areav for thedeposition of a liquid, which of the intermediate section. for the purposes oi the present description will The intermediate section of the casing is sepabe referred to as milk. f rated from the lower section by a lower partition A further object of the invention is to provide wall I'8 against which the ends of the respective lol for the complete enclosure of the drying surfaces, Sections abut,- the lower section beingy provided 10 which are of tubular conguration, so that the with a ange I9 and the upper sectionv with a milk will not be exposed to contamination and in connected ring through which bolts 2| are enorder that the heat'may be conserved to the uttered for securingl the sections rigidly together most extent. and in a manner to seal the interior of the casl The invention in particular relatesto the form ing against the admission of air. 15 and arrangement of the tubular drying surfaces The upper and lowerpartition walls,` in conand the enclosure provided therefor; to the arjunction, provide an intermediate heating chamrangement and means for operating the rotary bery 22r through which extend agroupof tubes Scrapers which remove the dried imilk from the 23, six beingfshown .in the present instance for 20 surfaces upon which the milkiis deposited; to purposes of illustration. The tubes are vopen at 20 the form and arrangement of the spray nozzles their ends,l and their inner wallsafford the dryand the means for supplying milk thereto; to the ingsurfaces for the deposition of the milk which means for imparting movement to the operating is dried by the heat conducted through the relaparts, and to the general structure and arrangetively thin walls of the tubes which areprefer- 25 ment of the apparatus as a'whole. ably of copper, which is vnon-corrosive and a good 25 Further objects and details Will appear from conductor of heat. t the description of the invention in conjunction The heating chamber is preferably heated by with the accompanying drawings, whereinsteam admitted through a pipe 24, or in any other Figure l is a sectional elevation of the rentire suitable manner, and if desired,a partial vacuum apparatus; may be maintained within the heating chamber 30 Fig. 2 is a sectional plan view taken on line in ordertoY circulate steam ata relatively low 2 2 of Fig. 1; f temperature, so that the drying will be carried Fig. 3 is a sectional plan view taken on line on under conditions which will not impair the 3-3 of Fig. l; flavor or quality of the"resulting'product.

ZIT Fig. 4 is a perspective detail partially in sec- In addition to the drying tubes 23, a well 25 -35 tion of the ratchet mechanism for imparting rois provided, which extends through the center of tation to the scraper knives and nozzles; the heating chamber and is closed at the lower Fig. 5 is a fragmental plan view showing the end by a plate 26 which furnishes a mounting for gear train for intermittently rotating the knives a 'fixed post or column 21, which is Aenlarged at and nozzles; its upper end 28 and provided with a helical '40 Fig. 6 is an enlarged detail of the knives and groove 29 which receives a dog 39 protruding inmountings therefor; .and wardly from a spring backed ratchet ring 3| hav- Figs. 7 to 1l inclusive are perspective details ing saw teeth 32 on its upper face, which teeth of the trip mechanism for actuating the valves at present abrupt faces in one direction only. 4V various stages in the operation. f The ratchet ring is mounted within a flanged .45

The structure as a whole is housed within a cup 33 Whichencircles the post 28 and affords casing comprising a cylindrical base section I0, a housing for the spring 34 which bears against a cylindrical intermediate section I I, and an the ratchet ring and tends to force the same upupper section I2 which is pear shaped in cross wardly with"a light degree of pressure. The 5o section, being provided on one side with a proratchet ring coa-cts withratchet teeth 35 on the v,50 tuberant portion I3 which affords a housing for lower face of a center spur gear 36 which meshes certain of the ope-rating parts presently to be with a group of spur'pinions 31 (six in number described. as shown), each of the spur pinions being keyed The intermediate and upper sections` of the upon a tubular shaft 38 which shafts are axially 5:. casing are separated by a cross .partition Wall I4, aligned with 'the centers of the drying tubes and I55 the apparatus as to provide a relatively large tion and a ring- If'l ywhich is secured to the rim '5" are adapted to be lowered into and raised therefrom concurrently with the imparting of rotation to each of the tubular shafts.

Each of the tubular shafts is journallecl through an upper plate 39 secured at the lower end of a sleeve 40 which encircles the upper end 28 of the post 27, which post is rigidly supported at its upper end within a plate4lv secured to the roof plate 42 which constitutes a cl- Asure for the upper end of the casing. '4

The tubular shafts 38 are also journalled through a ring-shaped plate 43 to which the cup 33 is secured, which arrangement serves to hold and steady the tubular shafts and maintain them in properly aligned relation withthe respective drying tubes.

The group of tubular shafts 38 terminate in a ring-shaped header 44, whichfsuppliesmilk vor other liquid to the interior of the tube shafts, so,

that said shafts aiord conduits for theu conveying of milk to the pointsv of :dischargewhich in each instance is through a groupofradiallyarranged nozzles 45 carried `by'therespective tube shafts near the lowerl endsthereof, each'nozzle being provided with anoutwa'rdly direotedaper'# ture 46 adapted to Adischarge "liquid 'directly against'V the interiorl wall 'ofthe associated' drying tube lwhen the nozzleigroup- -hasbeen lowered thereinto in a manner presently tube-.describedl Each ofthe tube shafts; at its lower end and below the nozzle group,carries a` s'pider- 41 having radially arranged arms 48;'alnd' each arm` at its 'outer end alfords a mounting for.' afscrape'r knife blade 49 having a cutting edge 50 which extends vertically, exceptat its lower terminus'v5l',v which is inturned'to afford an easy entrance intothe mouth of the drying tube. -f '1.1. 1 1 f yThe `kniiefedges stand in'obliquefrelation to `the `inner vsurface ofthe t'ube'rwall andvv present their edges forwardly in the'direction of .rotation of the spider which carries 'the' lgroup ofY knives, so that when' the tube shaft is `lower'edland simultaneously rotated',Y the knives will closely en` gage the inner surface offthe tube'and-scrape and remove the dry milk or'other dried material accumulatedthereon. "l .rl

.'Between "the knifel group and 'the nozzle group 'is located a shallowdrip pan 52 whichserves to arrest any drippings vfrom the;nozzles when'ele vated. u r f' I '2 Milk is supplied to the header 44 through fa 'flexible hose 53, which connects through the :wall ofthe upper section 'of theeca'sing `with-Yan` exteriorly'located supplypipe 54; -Thesupply pipe has its lower end enteredV into a `U-shaped coupling 55, one branch offwhich receivesa'supply 'pipe 56 -and the other branch-of which: receives 'an exhaust pipe 51. Y u 'f' As shown in Figs. '7 to yl1.inclusivathesupply "pipe 56 is'contr'olled by a .Valve 58and1the ex- Yhaust pipe by Ia valve 59,- :both valves being lmounted uponv a common lvalv'e'stem` 60, so ,that the two valves will be rotated infunison. g The valve 58 carries an arm lstotheouter end of which is pivoted a knife-'blade trip nger`:62, which is.' rigid againstvyieldir'ig'to av downward lthrust, but will yield, as yshown in Fig'. l0,l upon anfupward thrust. I i 1 The'valve arm 6| operates againsta'coil spring "63, sothat theisupply valv'ewill normally occupy 'the closed position 'shown inFig. 7 with the eX-' :haust' valve occupying the openposition indicated in the same ligure.

The group of tubular arms with the mountings provided therefor are adapted to be raisedand lowered upon the center post or standard 2B by the raising and lowering of an arm 64, which engages the upper end of the sleeve 40, which also supports the gear train and associated parts, and vertical movements are imparted to the arm 64 by a thrust rod 65, which is entered through a packing 66 in the offset bottom wall 61 of the upper section of the casing. The arm 64'is guided; by engagement with a guide rod'68 which stands in parallel adjacent relation t`o the thrust `rod 65. The thrust rod at its lower end carries arack 69 which at its lower end is provided with an arm 1D which is guided upon the guide rod 68. The rack meshes with a driving gear 'Il on a shaft .f'IZJoarrying a sprocket 'i3 upon which is mounted asprocket chain '14 driven from a sprocket wheel 'i5 on a motor shaft '16.

The rack `is provided with a trip bar Tl which as the. rack descends will engage the trip nger 62 in the manner shown in Figs. 7 to 11 inclusive, and :on itsv descent will engage the trip linger and depress it as in Figs. 7 and 8 so long as the iinger is inwcont'act with the bar, and will allow it to return to .the normal position shown in Fig. 9 when the trip bar descends to its lowermost po,- sition.,l Thereafter, `upon the return movement of thetripxbar, it will throw back the trip finger 62 so that the upward movement of the trip bar will lbeineiective to disturb the normal position of Atl'ie-zvalves', which as shown is one in which the milk supply line is closed and the vacuum or exhaust line is open. l y "The bottom section of the casing affords a chamber for the accumulation and removal of thedried'product, the section being closed by a dish-shaped base plate 'i8 having a discharge aperture' TQ-.inits center, below which is located a worm feed 80 which serves to convey the dried material to the point of discharge. A man-hole 3l closed by a cover 82 affords access to the'in-` terior of* the base portion of the casing, anda sightiglass V83 permits visual inspection as occasionY may require. Access into the upper poi'- tion `of the casing is permitted through a man` hole 84. Although no means are shown for exhausting the vapors from the interior of the casing, this forms no portion of the present invention, since any conventional means may be employed for this. purpose.

, Operation In operation, steam or other heating medium will be admitted to the interior of the heating chamber, and will serve to heat the walls of the dryingy tubesl to the desired degree. With the vtube shafts and associatedparts elevated as in Fig. 1, the milk supply` will be cut off, and the interior of the casing, with the exception of the heatingchamber, may be subjected to partial vacuum by the opening of the exhaust line.

Whenrotation is imparted to the sprocket 1l, the rack will be drawn downwardly and the entire operating assembly will be lowered, with the dog 36- (Fig. 4) in` engagement withthe helical groove 29, which causes a rotation of the spring backed ratchet ring 3| which will engage with theratchet teeth on the center gear 36. Rota-v ,tion will thus be imparted to each of the pinions 3l, andthe tube shafts 38 with the parts carried thereby:V Thus, as the assembly descends, the l -respective knife groups and spray nozzles will enter the respective drying tubes while rotating, and at the instant when the spray nozzles enter .the mouths of the respective tubes the valves will be actuated to admit milk or other liquid through the supply line and simultaneously cut off the exhaust line.

Thus, as the spray nozzles descend, they will rotate to discharge the milk in the form of a ne spray upon the heated surfaces of the drying tubes, so that after the rst cycle of operations the milk thus deposited will be dried and in condition for removal by the operation of the knives. On the second, and all succeeding operations, the knives, as they rotate with their edges presented forwardly, will scrape oif the dried milk previously deposited in advance of the discharge of a new charge of lmilk from the nozzles, each preceding charge being removed in preparation for a new deposit of milk.

Although the knives and nozzles rotate on thel descending movement, they will be held against rotation on the return movement, by reason of the fact that the teeth of the ratchet ring 3| will slip freely under the teeth 35 on the center gear 35, the spring 34 yielding to the extent necessary to permit such slippage. Since the knives stand in non-rotating relation on the upward movement, with their cutting edges aligned with the direction of movement, the knives will not have the effect on the upward movement of disturbing the film of milk previously deposited on' the downward stroke, so that the upward movement will be an idle or ineffective movement. The Valve arrangement also is one which cuts off the discharge of the milk before the lupward movement begins, so that nothing will occur during this period which will disturbi the drying operation being performed on the surfaces of the drying tubes.

As the lm of dried milk is scraped free by the rotation of the knives, the flaky material will fall downwardly into the lower section of the casing, which serves as an accumulating chamber and will be removed therefromby the action of the worm feed and discharged at some' convenient point.

By properly proportioning the length of the heating tubes with relation to the periods of time embraced in the cycle of operations, it is possible to so conduct the operations that a sufficient period will elapse between eachdeposit of milk on the tubular drying surfaces to permit the necessary drying before the material is removed by the descent of the knives, and it is also possible to so actuate the mechanism as to provide fora quick return movement after the deposition of av charge of milk, and an interval of rest thereafter to permitl the charge to be fully dried before its removal. It will be understood, therefore, that the timing of the device will depend upon the extent of the drying required and the nature of the liquid dealt with.

The arrangement is one which is extremely compact, and in view of the fact that the apparatus stands vertically, a minimum of floor space will be required, and if desired a series of driers can be grouped together and operated from a' common source of power.

By providing tubular drying surfaces of the character described, the area provided for the deposition of the milk can be greatly increased in comparison'with the surface afforded by a drum drier of comparable dimensions,` and in view of the fact that the drying surface is afforded by tubes which stand stationaryv there will be no necessity for the vheavy and rugged construction commonly employed in drum driers, or for an expenditure of the amount of power required in the operation of" such devices'.r

Furthermore, the present apparatus is one in which the principal working parts are completely enclosed, and in which the supply and distribution of the milk or other liquid is automatically controlled, so that no opportunity is afforded for the contamination of the product or the befouling of the apparatus by drippings or the like, since the supply of milk is automatically cut off as the nozzles are lifted from the drying tubes and subjected to the suction of the exhaust line, any slight drippings from the nozzles being caught by the pans provided for suchv purpose.

Although the invention has been described with full particularity, it will be understood that the vnumber and arrangement of the drying tubes may be increased or diminished, and the means for rotating and lifting the knives and nozzles may be modified, and that other details may be altered without departing'from the spirit dried, a plurality of tubular shafts aligned with the axes of the drying tubes and each having scraper means mounted upon its lower end, and spraying means ymounted behind the scraper means, means for admitting liquid to the tubular shafts for discharge through the spraying means,v and means for imparting endwise movement to the tubular shafts and adapted to bring the scraper means into scraping relation with the interior walls of the respective tubes to remove dried material therefrom concurrently with the deposition of a new charge of liquid upon the inner surfaces of the drying tubes, and means for imparting rotation to the spraying tubes concurrently ywith the downward movement thereof through the respective drying tubes and preventing rotation during the upward movement of the spraying tubes.

2. In a drier, the combination of a casing, a plurality of drying tubes within the casing and standing in parallel relation to one another with their intake ends at a higher elevation than their discharge ends and adapted to have their inner surfaces heated by a heating medium admitted to the casing, a standard mounted in adjacent relation to the tubes, a scraping device for each of the tubes and a header mounted upon the standard for supporting the group of scraping devices for longitudinal movement through the respective tubes and into contact with dried material upon the inner surfaces of the tubes, means for eifecting such longitudinal movement, spraying means associated with each of the scrapermeans and movable therewith behind the scraper means to deposit liquid on the tube surfaces after'. the removal of dried material previously deposited, and means for imparting rotary movements to the scraper means concurrently with the movement thereof through the tubes in a downward direction.

y3. In a drier, the combination of a casing, a plurality of drying tubes within the casing and standing in parallel relation to one another with their intake ends at a higher elevation than their discharge ends and adapted to have their inner surfaces heated by 'a heating medium admitted to. the casing, a standard mounted in adjacent relation to the tubes, a scraping'device for each of the tubes and a header slid-ably mounted upon the standard for supporting the group of scraping :devices and for longitudinal movement through the respective tubes and into contact with driedv material uponl the inner surfaces of the tubes, ymeans for" effectingv suchlongitudinal movement, spraying means coacting with the respective Scrapers for depositing liquid upon the tube surfaces behind the scraper means,and means for imparting rotary'movements yto the scraper means concurrently with the movement thereof through the tubes in a downward direction and adapted to prevent rotary movement 'of the scraper means on the ascending movement of the scraper'means. v4. Ina drier, the combination of a casing,=a pluralityof drying tubes within the casing, and standing inparallel relation to one another with their intake ends at a higher elevation than their discharge ends and adapted to have their inner surfaces heated by aheating medium admitted to the-casing, a fixed standard mounted in intermediate relationto the tubes,'a scraping device for each of the tubes and means slidably mounted -upon the' standard forsupporting the group of scraping devices for longitudinal movement through' the lrespective tubes and into contact with dried'material upon the inner Vsurfaces of the tubes,` means foreffecting such longitudinal movement, sprayingmeans,associatedV with cach of theI scraper means and movable'therewith behind the scraper means to deposit liquid von the tube surfaces after the removal of dried material previously deposited, and means for imparting rotary movements to the scraper means concurrentlywith the longitudinal movement thereof through `the tubes in a downward direction and adapted to prevent rotary movementk of the scraper means on the ascending movement of the scraper means.. i f f -5,- In a drier, the' combination'of a casing, a drying tube located within the casing and adapted to have its walls heated by a heating medium admitted-to the interior vof the casing, -a standard within the casing located in parallel relation/tothe drying tube and exteriorly thereof, a tubularshaft in aligned relation with the axis ofthe drying tube andmountings carried by thestandard for guiding the shaft during endwise movement with respect to the standard. knife mechanism carried by the tubular shaft at the lower end thereof Vand adapted toengage the inner surface of the drying tube for removal of dried material deposited thereon, means carried by the 4standard for imparting rotary movements to the tubular shaft concurrently with the advance movement thereof through the drying tube, and a spray nozzlecarried by the tubular shaft behind the knife mechanism for sprayingv liquidupon the' interior surface of the drying tube, means for imparting endwise advance and return movements to the tubular shaft and mechanisms carried thereby, and means for supplying liquid to the tubular shaft for discharge through the spray nozzle.

6. In'a drier, the combination'of a casing,a drying tube located within the casing and adapted to-have its walls heatedv by a heating medium admitted to the interior of the casing, a standard Within the casing located in parallel relation tothe drying tube and exterior-'ly thereof,y a tubular` shaft in aligned relation with the axis ofthe drying tubeand mountings `carried by the standardwfor'guiding the shaft during endwise movement with respect to the standard, knifemechanism carried by the tubular shaft at the lower end thereof and adapted to engage the inner surface of the drying tube for removal of dried material deposited thereon, means carried by the standard for imparting rotary movements tothe Ytubular shaft concurrently with the advance movement thereof through the drying tube andadapted toy prevent rotarymovements on the return movement of the tubular shaft, and a spray nozzle carried by the tubular shaftbehindv the knife mechanism for spraying liquid upon the interior surface'of the drying tube, means for imparting endwise advance and return movements to `the tubular shaft and mechanisms carried thereby, and means for supplying liquid to the tubular shaft for discharge through the spray nozzle.

7., In a drier, the combination of a casing, a drying tube located within the casing and adapted to have its walls heated by a heatingl medium admitted to the interior of the casing, a standard within the `casing located in parallel relation to the drying tube and exteriorly thereof, a tubular shaft' in aligned relation with the axisv of the: drying tube and mountings carried by the standard -for guiding the shaft during endwise movement with respect to the standard, knife mechanism carried by the tubularshaft at the lower end thereof and adapted to engage the inner surface ofthe drying tube for removal of dried material'deposited thereon, means carried by the standard for imparting rotary movements to the tubular shaft concurrently with the advance-movement thereof through the drying tube, and a spray nozzle carried by thetubular shaft behind the knife mechanism for spraying liquid upon the interior surface of the drying tube, means for imparting endwise advance and return movements to the tubular shaft and mechanisms carried thereby, and means for supplying liquid to the tubular shaft for discharge through the spray nozzle, and automatic means for controlling the flow of liquid vtherethrough and adapted to admitliquid during the advance movement ofthe nozzle and shut 01T the supply of kliquid during `the return movement of the nozzle. 8. In a drier, the combination` of a casing, a dryingtube located within the casing and adapted to have its IWalls heated by a heating medium admitted to the interior of the casing, a standard within the casing located in parallel relation to the drying tube and exteriorly thereof, a tubular shaft in alignedrelation with the axis of the drying tube and mountings carried bythe standard for guiding the shaft during endwise movement with respect to the standard, knife mechanism carried by the tubular shaft at the lower end thereof and adapted to engage the inner surface of the drying tube for removal of dried material deposited thereon, means carried by the standard for imparting rotary movements to the tubular shaftconcurrently with the advance movement thereof through the drying tube and adapted to prevent rotary,` movements on theV return movement of the tubular shaft, and a spray nozzle carried by the tubular shaft behind the vknife mechanism for spraying liquid upon the interior surface of the drying tube, means for imparting endwise advance and return movements' vto the tubular shaft and mechanisms carried thereby, and means-for supplying liquid to the tubular shaft for ldischarge through the spray nozzle, and automatic means for controlling the flow of liquid vtlfierethrough and adapted to admit liquid during the advance movement of the nozzle and shut off the supply of'liquid during the return movement of the nozzle.

9. In a drier, the combination of a casing, an open-ended drying tube within thecasing adapted to have its walls heated by a'heating medium admitted to the casing, a tubular shaft standing in axial aligned relation with the drying tube, a standard within the casing" extending in parallel relation to the drying tube, mountings for the tubular shaft carried bythe standard, means engaging said mountings rfor. imparting advance and return movements thereto, a gear slidably K and rotatably mounted upon the standard, means for imparting rotation to the gear during end- 'wise advance movement thereof along the standard, including a spiral and a member associated With the gear and engaging said spiral, a pinion on the tubular shaft in mesh with the gear first mentioned, means for admitting liquid to the interior of the tubular shaft, a cutting blade carried by the tubular shaft in position to engage the inner surface of the drying tube and remove dried material deposited thereon when rotation is imparted to the cutting blade, and nozzle means carried by the tubular shaft behind the cutting lade for spraying liquid upon the inner surface of the drying tube behind the cutting blade.

l0. In a drier, the combination of a casing, an open-ended drying tube within the casing adapted to have its walls heated by a heating medium admitted to the casing, a tubular shaft standing in axial aligned relation with the drying tube, a standard Within the casing extending in parallel relation to the drying tube, mountings for the tubular shaft carried by the standard, means engaging said mountings for imparting advance and return movements thereto, a gear slidably and rotatably mounted upon the standard, means for imparting rotation to the gear during endwise advance movement thereof along the standard, including a spiral and a member associated with the gear and engaging said spira] and adapted to be disengaged from the gear during the return movement thereof, a pinion on the tubular shaft in mesh with the gear first mentioned, means for admitting liquid to the interior of the tubular shaft, a cutting blade carried by the tubular shaft in position to engage the inner surface of the drying tube and remove dried material deposited thereon when rotation is imparted to the cutting blade, and nozzle means carried by the tubular shaft behind the cutting blade for spraying liquid upon the inner surface of the drying tube behind the cutting blade.

11. In a drier, the combination of a casing, an open-ended drying tube within the casing adapted to have its Walls heated by a heating medium admitted to the casing, a tubular shaft standing in axially aligned relation with the drying tube, a standard within the casing extending in parallel relation to the drying tube, mountings for the tubular shaft carried by the standard, means engaging said mountings for imparting advance and return movements thereto, a gear slidably and rotatably mounted upon the standard, means for imparting rotation to the gear during endwise advance movement thereof along the standard, including a spiral and a member associated with the gear and engaging said spiral, a pinion on the tubular shaft in mesh with the gear first mentioned, meansl for admitting liquid to the interior of thetub'ular shaft,'a cutting blade carried by the tubular shaft in position to engage the inner surface ofthe drying tube and remove dried material deposited thereon when rotation is imparted to the cutting blade, and nozzle means.v carried by the tubular shaft behind the cutting blade for spraying liquid upon thefinner surface of the drying tube behind the cutting blade, and automatic means for permitting the flow of liquid to the nozzle during the advance movement thereof and cutting off the supply of liquid during the return movement.

12. In a drier, the combination of la casing, an open-ended drying tube Within the casing adapted to have its walls heated by a heating medium admitted to the casing, a tubular shaft standing in axially aligned relation with the drying tube, a standard within the casing extending in parallel relation to the drying tube, mountings for the tubular shaft carried by the standard, means engaging said mountings for imparting advance and return movements thereto, a gear slidably and rotatably mounted upon the standard, means for imparting rotation to the gear during endwise advance movement thereof along the standard, including a spiral and a member associated with the gear and engaging said spiral and adapted to be disengaged from the gear during the return movement thereof, a pinion on the tubular shaft in mesh with the gear rst mentioned, means for admitting liquid to the interior of the tubular shaft, a cutting blade carried by the tubular shaft in position to engage the inner surface of the drying tube and remove dried material deposited thereon when rotation is imparted to the cutting blade, and nozzle means carried by the tubular shaft behind the cutting blade for spraying liquid upon the inner surface of the drying tube behind the cutting blade, and automatic means for permitting the flow of liquid to the nozzle during the advance movement thereof and cutting off the supply of liquid during the return movement.

13. In a drier, the combination of a liquid drying tube, means for heating said tube, a spraying device mounted to deposit a limited quantity of liquid to be dried on the interior surface of said tube, a knife presenting its cutting edge forwardly and in substantial alignment with the axis of the tube, and means to reciprocate the knife edgewise through the interior of the drying tube and to rotate the knife during one direction only of movement thereof to scrape the dried material from the inner surface of the drying tube.

14. In a drier, the combination of a casing, means for admitting a heating medium to said casing, a plurality of open ended liquid drying tubes within the casing having their intake ends at a higher elevation than their discharge ends and adapted to have their walls heated by said heating medium and to present their inner surfaces for the deposition of liquid to be dried thereon, a plurality of tubular shafts aligned respectively with the axes of the drying tubes and each having scraper means mounted upon its lower end and spraying means mounted behind the scraper means, means for admitting liquid to the tubular shafts for discharge through the spraying means, and means for imparting endwise movement to the tubular shafts to bring the scraper means into contacting relation with the interior walls of the respective tubes on the downward movement of the scraper means to remove the dried material previously deposited thereon by the spraying means concurrently with the deposition behind the scraper means of a new charge of liquid to be dried, and means adapted to impart rotation to the tubular shafts and scraper means concurrently with the downward movement only thereof through the respective drying tubes to effect scraping during such downward movement and to suspend rotation during the upward movement.

`15. In a drier, the combination of a casing, means for admitting a heating medium to said casing, a plurality of drying tubes within the casing and standing in` parallel relation to one another With their intake ends at a higher elevation than their discharge ends and adapted tol have their inner surfaces heated' by said heating medium, a standard mounted in intermediate relation 4to the tubes, a scraping device for each of the tubes, a header mounted upon the standard for supporting the group of scraping devices and adapted to reciprocate to move the scraping devices longitudinally through the re spective tubes in a manner to scrape previously deposited dried material from the inner surfaces of the tubes while moving in the downward direction and to suspend the scraping action while moving in the upward direction, spraying means coacting with the respective scrapers for depositing liquid upon the tube surfaces behind 'the scraper means, and means for imparting reciprocating movements to the header.

JULIUS F. DIETRICH. 

